#include <iostream>
using namespace std;

#include <vector>

class Solution 
{
public:
    void reverseString(vector<char>& s) 
    {
        int left = 0;
        int right = s.size() - 1;

        while (left < right)
        {
            swap(s[left], s[right]);
            ++left;
            --right;
        }
    }
};
